The main aim of the service — anticipating what users might want to know and supplying results before they enter a search query — echoes a line of experiments dating back to when Marissa Mayer, who went on to head Yahoo, was one of its main product managers.

“They’ve been trying to do this a long time,” said Greg Sterling, a US search engine analyst. The rise of smartphones has made this a more pressing need, since people are less likely than they are on PCs to spend time on Google’s service clicking through search results to research a topic, he said.

Mr Gomes said that “the vast majority” of Google’s searches were now conducted on mobile devices. “The needs and expectations of users have changed.”